Heat and sound insulating material



Patented Dec. 27, 1932 UNITED STATES PATENT OFFICE ELTON R. DARLING, OFDANVILLE, ILLINOIS, ASSIGNOR TO THE PACIFIC LUMBER COM.- PANY, OF SANFRANCISCO, CALIFORNIA, A CORPORATION OF IMAINE HEAT AND SOUND INSULATINGMATERIAL No Drawing.

The present invention relates to an improved dry material for use as afiller and as a thermal and sound insulating substance.

One of the objects of the invention is to provide a material in loose,powdered form that may be placed between the floor of a building toserve as a thermal and sound insulator.

Another object of the invention is to employ a material which, fordearth of a better designation, is here designated as tree sand, whichis a waste material resulting from the manufacture of sheathing lumberand wall board from the bark of the California redwood or Sequoia tree.

Another object of the invention is to employ a very lightweightinorganic material known as zonolite, sometimes also called vermiculite,in admixture with the said tree sand in order to obtain a material oflighter specific gravity.

In producing the improved thermal and sound insulating material, I firsttake the mineral known as zonolite, which is a variety of micacontaining water in combination, and heat it to cause it to expand andform a very light and fluffy material. This property of zonolite ispeculiar to this mineral and yields a product having a very low specificgravity.

In order to exfoliate or expand this mate rial it serves to heat thesame to a temperature of not in exces of 400 0., whereafter it is cooledand preferably roughly ground to disintegrate it.

The so-called tree sand is a natural organic product inherent in thebark of California giant redwood trees, and consists of small discrete,rounded. blackish grains that are substantially incombustible. This treesand occurs in the bark intermediate of the fibres of the latter and isremoved therefrom in the manufacture of sheathing lumber in adry-sieving operation. The tree sand may, moreover, be separated fromthe fibres by a process of elutriation in which the fibres and the treesand are simultaneously suspended in a slowly-moving current of waterunder such conditions that there is slight agitation, sufiicient tomaintain the fibres in suspension but insuflicient to prevent deposi-1929. Serial No. 381,083.

tion of the tree sand by subsidence. If the tree sand is derived by thiselutriation process it is necessary to dry the same, but this is readilyaccomplished by spreading it loosely in the sun. Of course, a rotaryhot-air drier will serve the purpose equally well.

In either case, the preferred thermal and sound insulating compositionconsists substantially of three parts by weight of tree sand and onepart of the exfoliated zonolite, these substances being thoroughly intermingled by mechanical means and sold to the consumer in bags, barrelsand other suit able containers. Other proportions may be used, as, forexample, equal parts of zonolite and tree sand, this latter forming astill lighter material. As the tree sand is an absolute waste at presentand in the manufacture of sheathing lumber from redwood bark is producedas a by-product in enormous quantities, its price is very low and hencethe cost of the composition is very reasonable and the product thereforeof distinct commercial value, as fillers of this type must be cheap andeffective in order to compete with ordinary sand or industrial wasteshitherto used for similar purposes.

It is to be distinctly understood that the proportions herein recitedare not limiting in any sense, since the invention is to be construedonly by the hereunto appended claims: r

I claim:

1. A heat and sound insulating composition consisting of substantiallythree parts by weight of rounded sand-like particles of organic matterderived from redwood bark and one part by weight of exfoliated zonolite.wherein the zonolite prevents excessive packing together of saidparticles, thereby increasing the sound and heat-insulating value of theindividual particles.

2. Composition of matter for use as a sound and heat insulatingmaterial, consisting of exfoliated zonolite and tree-sand, the latterbeing derived from redwood bark.

In witness whereof, I have hereunto subscribed my name.

ELTON R. DARLING.

